Disqus comment system was causing javascript errors, which in chrome console looked something like this:
Uncaught Syntax error, unrecognized expression: [href=edit-comments.php?page=disqus]
It caused unmovable widgets, screen-options didn’t open and other related javascript issues in admin panel.
After some researching it turns out, there’s a simple fix.
In /wp-content/plugins/disqus-comment-system/disqus.php, find:
href=edit-comments.php?page=disqus
and replace it with:
href=”edit-comments.php?page=disqus”
Cheers